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CN-224203512-U - Optical imaging system and endoscope

CN224203512UCN 224203512 UCN224203512 UCN 224203512UCN-224203512-U

Abstract

The application discloses an optical imaging system and an endoscope. The optical imaging system comprises a first lens, a second lens, a third lens, a triple-cemented lens group, a double-cemented lens group and a steering prism which are sequentially arranged from an object side to an image side. The object side surface of the first lens is a convex surface at the optical axis, the image side surface of the first lens is a concave surface at the optical axis, the second lens is a 30-degree turning prism, the object side surface of the third lens is a plane, the image side surface of the third lens is a convex surface, the object side surface and the image side surface of the fourth lens in the three-cemented lens group are both convex surfaces, the object side surface and the image side surface of the fifth lens are both concave surfaces, the object side surface and the image side surface of the sixth lens are both convex surfaces, the object side surface of the seventh lens in the two-cemented lens group is a plane, the image side surface of the seventh lens is a convex surface, the object side surface of the eighth lens is a concave surface, and the image side surface of the eighth lens is a convex surface. The optical imaging system and the endoscope provided by the application at least can solve the problems of larger caliber and larger imaging distortion of the optical imaging system of the endoscope.

Inventors

  • LIANG RUI
  • ZHAO XUAN

Assignees

  • 杭州海康慧影科技有限公司

Dates

Publication Date
20260505
Application Date
20250521

Claims (10)

  1. 1. An optical imaging system, characterized by comprising a first lens (10), a second lens (20), a third lens (30), a triple cemented lens group (40), a double cemented lens group (50) and a turning prism (60) which are sequentially arranged from an object side to an image side, The object side surface and the image side surface of the first lens element (10) are aspheric, the object side surface of the first lens element (10) is convex at the optical axis, and the image side surface of the first lens element (10) is concave at the optical axis; the second lens (20) is a 30 DEG turning prism; The object side surface of the third lens (30) is a plane, and the image side surface of the third lens (30) is a convex surface; The three-cemented lens assembly (40) comprises a fourth lens (41), a fifth lens (42) and a sixth lens (43), wherein the fourth lens (41), the fifth lens (42) and the sixth lens (43) are spherical lenses, the object side surface and the image side surface of the fourth lens (41) are convex surfaces, the object side surface and the image side surface of the fifth lens (42) are concave surfaces, and the object side surface and the image side surface of the sixth lens (43) are convex surfaces; the double-cemented lens assembly (50) comprises a seventh lens (51) and an eighth lens (52), wherein the seventh lens (51) and the eighth lens (52) are spherical lenses, the object side surface of the seventh lens (51) is a plane, the image side surface of the seventh lens (51) is a convex surface, the object side surface of the eighth lens (52) is a concave surface, and the image side surface of the eighth lens (52) is a convex surface.
  2. 2. The optical imaging system according to claim 1, wherein the optical imaging system satisfies a relation of 4≤TTL/ImgH≤4.5, wherein TTL is an optical path distance between an object side surface of the first lens (10) in the optical imaging system and an imaging surface of the optical imaging system on an optical axis, and ImgH is an imaging surface maximum image height.
  3. 3. The optical imaging system of claim 1, wherein the optical imaging system satisfies a relationship of 6.2≤f/EPD≤6.5, where f is an effective focal length of the optical imaging system and EPD is an entrance pupil diameter of the optical imaging system.
  4. 4. The optical imaging system of claim 1, wherein the optical imaging system satisfies the relationship D≤3.6 mm, where D is the maximum diameter of the optical imaging system.
  5. 5. The optical imaging system of claim 1, wherein the optical imaging system satisfies the relationship 1.9mm +.f.tan (Semi-FOV) +.2.1 mm, where f is the effective focal length of the optical imaging system and Semi-FOV is half of the maximum field angle of the optical imaging system.
  6. 6. The optical imaging system according to any one of claims 1 to 5, characterized in that the effective focal length f 1 of the first lens (10) satisfies the relation-1.95 mm < f 1 < -1.88mm.
  7. 7. The optical imaging system according to any one of claims 1 to 5, characterized in that the effective focal length f 3 of the third lens (30) satisfies the relation 3.45mm < f 3 <3.62mm.
  8. 8. The optical imaging system according to any of claims 1 to 5, characterized in that the effective focal length f 456 of the triple-cemented lens group (40) satisfies the relation 11.8mm < f 456 <12.5mm, and/or, The effective focal length f 4 of the fourth lens (41) satisfies the relation 5mm < f 4 <6mm, and/or, The effective focal length f 5 of the fifth lens (42) satisfies the relation-3 mm < f 5 < -2mm, and/or, The effective focal length f 6 of the sixth lens (43) satisfies the relation 3mm < f 6 <4mm.
  9. 9. The optical imaging system according to any one of claims 1 to 5, characterized in that the effective focal length f 7 of the seventh lens (51) satisfies the relation 4mm < f 7 <4.5mm, and/or, The effective focal length f 8 of the eighth lens (52) satisfies the relation-5.8 mm < f 8 < -5.2mm, and/or, The sum of the difference between the effective focal lengths of the seventh lens (51) and the eighth lens (52) and the effective focal lengths of the seventh lens (51) and the eighth lens (52) satisfies the relation-7.8 < - (f 7 -f 8 )/(f 7 +f 8 ) < -7.2.
  10. 10. An endoscope, characterized in that it comprises the optical imaging system of any one of claims 1 to 9.

Description

Optical imaging system and endoscope Technical Field The application relates to the technical field of medical instruments, in particular to an optical imaging system and an endoscope. Background Current endoscopes include optical endoscopes and electronic endoscopes. Among them, an optical endoscope is generally composed of an optical imaging system and an optical image-transmitting system, which rely on high-quality optical elements. The electronic endoscope images the observed object on an electronic imaging element such as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS), and the like, and adopts a CCD or CMOS imaging element with high resolution, so that the imaging has the effects of high resolution and vivid color. It is typically imaged by a front-end miniature optical system, comprising a plurality of lens groups responsible for focusing the information of the object under observation onto an imaging element. Endoscopes in the prior art generally employ a large caliber design to obtain a greater amount of light input, thereby improving the brightness of the image. However, the large-caliber design of the endoscope optical imaging system has the problems of large imaging distortion, huge system volume and high manufacturing cost. Disclosure of utility model The application mainly aims to provide an optical imaging system and an endoscope, which are used for solving the problems of larger caliber and larger imaging distortion of the optical imaging system of the endoscope. According to an aspect of the present application, there is provided an optical imaging system including a first lens, a second lens, a third lens, a triple cemented lens group, a double cemented lens group, and a turning prism sequentially disposed along an object side to an image side, wherein, The object side surface and the image side surface of the first lens are aspheric, the object side surface of the first lens is a convex surface at the optical axis, and the image side surface of the first lens is a concave surface at the optical axis; The second lens is a 30-degree steering prism; the object side surface of the third lens is a plane, and the image side surface of the third lens is a convex surface; the third cemented lens assembly comprises a fourth lens, a fifth lens and a sixth lens, wherein the fourth lens, the fifth lens and the sixth lens are spherical lenses, the object side surface and the image side surface of the fourth lens are convex surfaces, the object side surface and the image side surface of the fifth lens are concave surfaces, and the object side surface and the image side surface of the sixth lens are convex surfaces; The lens assembly for the double-cemented lens assembly comprises a seventh lens and an eighth lens, wherein the seventh lens and the eighth lens are spherical lenses, the object side surface of the seventh lens is a plane, the image side surface of the seventh lens is a convex surface, the object side surface of the eighth lens is a concave surface, and the image side surface of the eighth lens is a convex surface. Further, the optical imaging system satisfies the relation of TTL/ImgH which is more than or equal to 4 and less than or equal to 4.5, wherein TTL is the optical path distance from the object side surface of the first lens to the imaging surface of the optical imaging system on the optical axis, and ImgH is the maximum image height of the imaging surface. Further, the optical imaging system satisfies the relation of f/EPD being 6.2-6.5, wherein f is the effective focal length of the optical imaging system, and EPD is the entrance pupil diameter of the optical imaging system. Further, the optical imaging system meets the relation that D is less than or equal to 3.6mm, wherein D is the maximum diameter of the optical imaging system. Further, the optical imaging system satisfies the relation that f (Semi-FOV) is less than or equal to 1.9mm and less than or equal to 2.1mm, wherein f is the effective focal length of the optical imaging system, and Semi-FOV is half of the maximum field angle of the optical imaging system. Further, the effective focal length f 1 of the first lens satisfies the relation-1.95 mm < f 1 < -1.88mm. Further, the effective focal length f 3 of the third lens satisfies the relation 3.45mm < f 3 <3.62mm. Further, the effective focal length f 456 of the triple-cemented lens group satisfies the relation 11.8mm < f 456 <12.5mm, and/or, The effective focal length f 4 of the fourth lens satisfies the relationship 5mm < f 4 <6mm, and/or, The effective focal length f 5 of the fifth lens satisfies the relation-3 mm < f 5 < -2mm, and/or, The effective focal length f 6 of the sixth lens satisfies the relation 3mm < f 6 <4mm. Further, the seventh lens has an effective focal length f 7 satisfying the relation 4mm < f 7 <4.5mm, and/or, The effective focal length f 8 of the eighth lens satisfies the relation-5.8 mm < f 8 < -5.2mm, and/or, The